The present invention relates generally to the field of optical communications and in particular to a high capacity, dense wavelength-division-multiplexed (DWDM) transmission arrangement.
The capacity of dense wavelength division multiplexed optical fiber communication systems is expanding rapidly due, in large part, to the demand created by voluminous amounts of data traffic and the Internet. Long-haul commercial DWDM systems, which are generally based upon silica erbium-doped fiber amplifiers (EDFA""s), are limited to a capacity of much less than 1 Tb/s due to the limited bandwidth of the EDFA""s.
Experimental long-haul transmission exhibiting 32xc3x9710 Gb/s capacity using wide band silica EDFA""s was reported by Y. Sun et al., in an article entitled xe2x80x9cTransmission of 32-WDM 10 Gb/s Channels over 640 km using Broad-band, Gain-Flattened Erbium-Doped Silica Fiber Amplifiersxe2x80x9d, that appeared in IEEE Photon. Technol. Lett., Vol. 9, No. 12, pp. 1652-1654 in 1997. The channel spacing for the arrangement was 100 GHz, which corresponds to an ITU standard. Subsequently, a transmission exhibiting 50xc3x9710 Gb/s capacity was reported by H. Tagu et al., in an article entitled xe2x80x9cA half Tbits/s (50xc3x9710.66 Gb/s), over 1600 Km Transmission Experiment using Widely Gain-flattened EDFA Chainxe2x80x9d, at ECOC 97 in Edinburgh, UK, Paper PD, pp. 13-16, 1997. In that experiment, the spacing between amplifiers was 50 kmxe2x80x94a much more suitable distance for such applications as trans-oceanic links. For terrestrial applications however, longer spans are preferable to further reduce the number of amplifiers in the transmission path.
Consequently, additional long distance transmission arrangements are desired.
We have developed a high-capacity optical transmission arrangement exhibiting 1 Tb/s transmission capacity. The arrangement comprises a plurality of optical sources and a plurality of wide-band optical amplifiers connected in series, wherein each individual amplifier includes a xe2x80x9csplit-bandxe2x80x9d architecture in which individual sub-bands of the optical energy traversing the amplifier are separated and then amplified in parallel prior to recombination and subsequent output.
Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention are described in detail below with reference to the accompanying drawing.